title: Emerging biomarkers for the diagnosis and prognosis of prostate cancer.
abstract: BACKGROUND
  Early detection of prostate cancer (CaP), the most prevalent cancer and the second-leading cause of death in men, has proved difficult, and current detection methods are inadequate. Prostate-specific antigen (PSA) testing is a significant advance for early diagnosis of patients with CaP.
  
  
  BACKGROUND
  PSA is produced almost exclusively in the prostate, and abnormalities of this organ are frequently associated with increased serum concentrations. Because of PSA's lack of specificity for CaP, however, many patients undergo unnecessary biopsies or treatments for benign or latent tumors, respectively. Thus, a more specific method of CaP detection is required to augment or replace screening with PSA. The focus recently has been on creating cost-effective assays for circulating protein biomarkers in the blood, but because of the heterogeneity of CaP, it has become clear that this effort will be a formidable challenge. Each marker will require proper validation to ensure clinical utility. Although much work has been done on variations of the PSA test (i.e., velocity, density, free vs bound, proisoforms) with limited usefulness, there are many emerging markers at various stages of development that show some promise for CaP diagnosis. These markers include kallikrein-related peptidase 2 (KLK2), early prostate cancer antigen (EPCA), PCA3, hepsin, prostate stem cell antigen, and alpha-methylacyl-CoA racemase (AMACR). We review biomarkers under investigation for the early diagnosis and management of prostate cancer.
  
  
  CONCLUSIONS
  It is hoped that the use of panels of markers can improve CaP diagnosis and prognosis and help predict the therapeutic response in CaP patients.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Girish
authors.initials: G
authors.lastname: Sardana
authors.forename: Barry
authors.initials: B
authors.lastname: Dowell
authors.forename: Eleftherios P
authors.initials: EP
authors.lastname: Diamandis
mesh_terms: D000951:Antigens, Neoplasm / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood*; D058851:GPI-Linked Proteins; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood; D009363:Neoplasm Proteins / Q000097:blood; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D019998:Racemases and Epimerases / Q000097:blood; D012697:Serine Endopeptidases / Q000097:blood; D020840:Tissue Kallikreins / Q000097:blood
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C110843:PSCA protein, human; C504719:early prostate cancer antigen, human; C479341:prostate cancer antigen 3, human; D012697:Serine Endopeptidases; C055645:hepsin; D020840:Tissue Kallikreins; D017430:Prostate-Specific Antigen; D019998:Racemases and Epimerases; C108352:alpha-methylacyl-CoA racemase